Oceanic controls on the primary production of the northwest European continental shelf: model experiments under recent past conditions and a potential future scenario

In this paper we clearly demonstrate that changes in oceanic nutrients are a first order factor in determining changes in the primary production of the northwest European continental shelf on time scales of 5–10 yr. We present a series of coupled hydrodynamic ecosystem modelling simulations, using the POLCOMS-ERSEM system. These are forced by both reanalysis data and a single example of a coupled ocean-atmosphere general circulation model (OA-GCM) representative of possible conditions in 2080–2100 under an SRES A1B emissions scenario, along with the corresponding present day control. The OA-GCM forced simulations show a substantial reduction in surface nutrients in the open-ocean regions of the model domain, comparing future and present day time-slices. This arises from a large increase in oceanic stratification. Tracer transport experiments identify a substantial fraction of on-shelf water originates from the open-ocean region to the south of the domain, where this increase is largest, and indeed the on-shelf nutrient and primary production are reduced as this water is transported on-shelf. This relationship is confirmed quantitatively by comparing changes in winter nitrate with total annual nitrate uptake. The reduction in primary production by the reduced nutrient transport is mitigated by on-shelf processes relating to temperature, stratification (length of growing season) and recycling. Regions less exposed to ocean-shelf exchange in this model (Celtic Sea, Irish Sea, English Channel, and Southern North Sea) show a modest increase in primary production (of 5–10%) compared with a decrease of 0–20% in the outer shelf, Central and Northern North Sea. These findings are backed up by a boundary condition perturbation experiment and a simple mixing model.

Natural iron fertilization of the Atlantic sector of the Southern Ocean by continental shelf sources of the Antarctic Peninsula

In large parts of the Southern Ocean, primary production is limited due to shortage of iron (Fe). We measured vertical Fe profiles in the western Weddell Sea, Weddell-Scotia Confluence, and Antarctic Circumpolar Current (ACC), showing that Fe is derived from benthic Fe diffusion and sediment resuspension in areas characterized by high turbulence due to rugged bottom topography. Our data together with literature data reveal an exponential decrease of dissolved Fe (DFe) concentrations with increasing distance from the continental shelves of the Antarctic Peninsula and the western Weddell Sea. This decrease can be observed 3500 km eastward of the Antarctic Peninsula area, downstream the ACC. We estimated DFe summer fluxes into the upper mixed layer of the Atlantic sector of the Southern Ocean and found that horizontal advection dominates DFe supply, representing 54 ± 15% of the total flux, with significant vertical advection second most important at 29 ± 13%. Horizontal and vertical diffusion are weak with 1 ± 2% and 1 ± 1%, respectively. The atmospheric contribution is insignificant close to the Antarctic continent but increases to 15 ± 10% in the remotest waters (>1500 km offshore) of the ACC. Translating Southern Ocean carbon fixation by primary producers into biogenic Fe fixation shows a twofold excess of new DFe input close to the Antarctic continent and a one-third shortage in the open ocean. Fe recycling, with an estimated “fe” ratio of 0.59, is the likely pathway to balance new DFe supply and Fe fixation.

Validation of the NEMO-ERSEM operational ecosystem model for the North West European Continental Shelf

This paper details updates to the Met Office's operational coupled hydrodynamic-ecosystem model from the 7 km Medium-Resolution Continental Shelf – POLCOMS-ERSEM (MRCS-PE) system (Siddorn et al., 2007) to the 7 km Atlantic Margin Model NEMO-ERSEM (AMM7-NE) system. We also provide a validation of the ecosystem component of the new operational system. Comparisons have been made between the model variables and available in situ, satellite and climatological data. The AMM7-NE system has also been benchmarked against the MRCS-PE system. The transition to the new AMM7-NE system was successful and it has been running operationally since March 2012 and has been providing products through MyOcean (http://www.myocean.eu.org) since that time. The results presented herein show the AMM7-NE system performs better than the MRCS-PE system with the most improvement in the model nutrient fields. The problem of nutrient accumulation in the MRCS-PE system appears to be solved in the new AMM7-NE system with nutrient fields improved throughout the domain as discussed in Sect. 4. Improvements in model chlorophyll are also seen but are more modest.

Particle export during a bloom of Emiliania huxleyi in the North-West European continental margin

Coccolithophores, the dominant pelagic calcifiers in the oceans, play a key role in the marine carbon cycle through calcification, primary production and carbon export, the main drivers of the biological CO2 pump. In May 2002 a cruise was conducted on the outer shelf of the North-West European continental margin, from the north Bay of Biscay to the Celtic Sea (47.0 degrees-50.5 degrees N, 5.0 degrees-11.0 degrees W), an area where massive blooms of Emiliania huxleyi are observed annually. Biogeochemical variables including primary production, calcification, partial pressure of CO2 (pCO(2)), chlorophyll-a (Chl-a), particle load, particulate organic and inorganic carbon (POC, PIC) and Th-234, were measured in surface waters to assess particle dynamic and carbon export in relation to the development of a coccolithophore bloom. We observed a marked northward decrease in Chl-a concentration and calcification rates: the bloom exhibited lower values and may be less well developed in the Goban Spur area. The export fluxes of POC and PIC from the top 80 m, determined using the ratios of POC and PIC to Th-234 of particles, ranged from 81 to 323 mg C m(-2) d(-1) and from 30 to 84 mg C m(-2) d(-1), respectively. The highest fluxes were observed in waters presenting a well-developed coccolithophore bloom, as shown by high reflectance of surface waters. This experiment confirms that the occurrence of coccolithophores promotes efficient export of organic and inorganic carbon on the North-West European margin.

Las familias "Baeomycetaceae" e I"Icmadophilaceae" en la Península Ibérica

Se aportan datos morfológicos, químicos y de distribución de seis especies de las familias Baeomycetaceae (Baeomyces) e Icmadophilaceae (Dibaeis, Icmadophila, Thamnolia) presentes en la Península Ibérica. Se publican numerosas nuevas citas de Baeomyces rufus y de Dibaeis baeomyces, que constituyen las especies más frecuentes y abundantes en la península.

Floristic notes of Sierra del Rincón Biosphere Reserve (Spain, Madrid province)

New records of vascular plants from Sierra del Rincón Biosphere Reserve and surroundings (Spain, Madrid province) are provided. It is noteworthy the presence of atlantic flora in this continental area and the different shrubby communities in different sectors with different litology: in areas with gneiss they are dominated by leguminous genisteae; where it is schistous, shale or quartzite they are heathlands.

Contribution to the knowlegde of Galician xenoflora (NW Iberian Peninsula, Spain).

Information on 12 exotic plants of diverse interest for the Galician flora are presented. All of them were collected in Ribeira council (SW of the A Coruña province). The total includes 8 novelties at a regional level (Aeonium haworthii, Aloe mitriformis, Brugmansia × candida, Nephrolepis cordifolia, Osteospermum ecklonis, Pelargonium capitatum, Sedum mexicanum, Sparaxis tricolor), and 2 provincial novelties. In addition, information on two taxa hardly mentioned in the literature on Galician vascular flora is also included. All the cited specimens are deposited at the SANT Herbarium.

Long-term iceshelf-covered meiobenthic communities of the Antarctic continental shelf resemble those of the deep sea

Since strong regional warming has led to the disintegration of huge parts of the Larsen A and B ice shelves east of the Antarctic Peninsula in 1995 and 2002, meiofaunal communities covered by ice shelves for thousands of years could be investigated for the first time. Based on a dataset of more than 230,000 individuals, meiobenthic higher taxa diversity and composition of Larsen continental shelf stations were compared to those of deep-sea stations in the Western Weddell Sea to see whether the food-limiting conditions in the deep sea and the food-poor shelf regime at times of iceshelf coverage has resulted in similar meiobenthic communities, on the premises that food availability is the main driver of meiobenthic assemblages. We show here that this is indeed the case; in terms of meiobenthic communities, there is greater similarity between the deep sea and the inner Larsen embayments than there is similarity between the deep sea and the former Larsen B iceshelf edge and the open continental shelf. We also show that resemblance to Antarctic deep-sea meiofaunal communities was indeed significantly higher for communities of the innermost Larsen B area than for those from intermediate parts of Larsen A and B. Similarity between communities from intermediate parts and the deep sea was again higher than between those of the ice-edge and the open shelf. Meiofaunal densities were low at the inner parts of Larsen A and B, and comparable to deep-sea densities, again likely owing to the low food supply at both habitats. We suggest that meiobenthic communities have not yet recovered from the food-limiting conditions present at the time of iceshelf coverage. Meiofaunal diversity on the other hand seemed driven by sediment structure, being higher in coarser sediments.

Modelling the combined impacts of climate change and direct anthropogenic drivers on the ecosystem of the northwest European continental shelf

The potential response of the marine ecosystem of the northwest European continental shelf to climate change under a medium emissions scenario (SRES A1B) is investigated using the coupled hydrodynamics-ecosystem model POLCOMS-ERSEM. Changes in the near future (2030–2040) and the far future (2082–2099) are compared to the recent past (1983–2000). The sensitivity of the ecosystem to potential changes in multiple anthropogenic drivers (river nutrient loads and benthic trawling) in the near future is compared to the impact of changes in climate. With the exception of the biomass of benthic organisms, the influence of the anthropogenic drivers only exceeds the impact of climate change in coastal regions. Increasing river nitrogen loads has a limited impact on the ecosystem whilst reducing river nitrogen and phosphate concentrations affects net primary production(netPP) and phytoplankton and zooplankton biomass. Direct anthropogenic forcing is seen to mitigate/amplify the effects of climate change. Increasing river nitrogen has the potential to amplify the effects of climate change at the coast by increasing netPP. Reducing river nitrogen and phosphate mitigates the effects of climate change for netPP and the biomass of small phytoplankton and large zooplankton species but amplifies changes in the biomass of large phytoplankton and small zooplankton.

Plagiomnium T. Kop. (Plagiomniaceae, Musci) en la Península Ibérica e llles Balears

Se ha realizado la revisión de ejemplares de Plagiomnium T. Kop., en la Península Ibérica, registrados en los Herbarios de España, Portugal y Francia, así como en algunas colecciones privadas. Siete taxones de Plagiomnium están representados en España: P. affine, P. cuspidatum, P. elatum, P. ellipticum, P. medium subsp. medium, P. rostratum y P. undulatum, y en Portugal cuatro taxones: P. affine, P. medium subsp. mediurn, P. rostratum y P. undulatum. En Mallorca (Illes Balears), queda excluido P. cuspidatum y P. elatum es nuevo para estas islas. P. undulatum, P. affine y P. rostratum son las especies más comunes en los bosques y zonas montañosas de la Península; P. cuspidatum y P. elatum son frecuentes en la mitad septentrional de España, siendo muy escasos en la parte meridional; los más raros son: P. ellipticum y P. medium subsp. medium, que están restringidos a los hábitats mesofíticos, suelos oligotrofos y húmedos de Pirineos, Cordillera Cantábrica y el piso supra-oromediterráneo de los Montes de Cataluña, Sistema Ibérico septentrional (Macizo de La Demanda) y Sistema Central. Se aportan fotografías de las esporas al SEM de P. affine, P. medium subsp. medium, P. rostratum y P. undulatum así como los mapas de distribución de cada taxon.

Precisiones nomenclaturales sobre la vegetación noroccidental ibérica

Se analizan nomenclaturalmente los nombres Cytietum striati, Genisto berberidae-Ericetum tetralicis, Erico australis-Ericetum arboneae, Junipeno nanae-Vaccinietum microphylli, Adenocarpo complicati-Ulicetum europaei, Sileno maritimae-Ulicetum humilis, Erico umbellatae-Genistetum sanabrensis, Ulici micranthi-Ericetum umbellatae y Myrtillo-Quercetum roboris.